Stabilized thickened hydrogen peroxide containing compositions with a mixture of stabilizers

ABSTRACT

Stabilized thickened hydrogen peroxide containing compositions are disclosed. The compositions contain a stabilizer system made up of a stannate stabilizer, a phosphorus containing stabilizer or a mixture of phosphorus containing stabilizers; and an aromatic chelating agent or a mixture of aromatic chelating agents. The compositions are suitable for use as disinfectants, as cleaning agents, and in various personal care applications such as hair care and tooth whitening.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.11/023,705, filed Dec. 28, 2004 now U.S. Pat. No. 7,045,493 which claimspriority on U.S. Provisional Application Ser. No. 60/586,682, filed Jul.9, 2004, incorporated herein by reference.

FIELD OF THE INVENTION

This invention relates to stabilization of hydrogen peroxide containingcompositions. In particular, this invention relates stabilized thickenedhydrogen peroxide containing compositions suitable for use in a varietyof disinfectant, cleaning, personal care, pharmaceutical, textile, andindustrial applications.

BACKGROUND OF THE INVENTION

To avoid the disadvantages inherent in the use of hypochlorite solutionsin cleaning compositions, manufacturers of these products have developedalternative compositions based on aqueous hydrogen peroxide. Hydrogenperoxide is generally acceptable from a toxicological and environmentalstandpoint because its decomposition products are oxygen and water. Inaddition, these compositions are also fiber-safe and color-safe.

Polymeric thickening agents are added to cleaning compositions toincrease their residence time on non-horizontal surfaces as well as toenhance the aesthetics of the composition, to provide ease of use, andto suspend other components of the composition. Decomposition ofhydrogen peroxide caused by catalytically active substances, such asmetal ions, is extremely difficult to prevent. In addition, many ofconventional polymeric thickening agents accelerate the decomposition ofhydrogen peroxide and are themselves unstable in the presence ofhydrogen peroxide. Thus, it has been extremely difficult to producecompositions that have the required stability. With excessivedecomposition of the hydrogen peroxide, the composition loses itscleaning ability. In addition, decomposition of the polymeric thickeningagent reduces the viscosity of the cleaning composition, reducing itsability to cling to non-horizontal surfaces.

Consequently, stabilizers have been developed to improve the stabilityof thickened hydrogen peroxide containing compositions. Stabilizers arediscussed, for example, in Ambuter, U.S. Pat. Nos. 5,997,764, and6,083,422, the disclosures of which are incorporated herein byreference. Although these stabilizers increase the shelf life ofthickened hydrogen peroxide containing compositions, none of thesestabilizers is totally satisfactory. Thus, a need exists for thickenedhydrogen peroxide containing compositions with increased stability.

SUMMARY OF THE INVENTION

The invention is a thickened hydrogen peroxide containing composition.The composition comprises:

-   a) about 0.5 wt % to about 15 wt % of hydrogen peroxide;-   b) water;-   c) about 0.05 wt % to 10 wt % of a polymeric thickening agent or a    mixture of polymeric thickening agents;-   d) a stabilizer system comprising:    -   i) about 10 ppm to about 1% of a stannate stabilizer;    -   ii) about 10 ppm to about 1% of a phosphorus containing        stabilizer or a mixture of phosphorus containing stabilizers;        and    -   iii) about 10 ppm to about 1% of an aromatic chelating agent or        a mixture of aromatic chelating agents; and-   in which the composition has a viscosity of greater than about 500    cP.-   Thickened hydrogen peroxide containing compositions that comprise    the three component stabilizer system are storage stable.

DETAILED DESCRIPTION OF THE INVENTION

Unless otherwise indicated, the terms phosphonic acid chelating agent,aromatic chelating agent, stannate stabilizer, surfactant, polymericthickening agent, pyrophosphate, aqueous base, and similar terms alsoinclude mixtures of such materials. Unless otherwise specified, allpercentages are percentages by weight (wt %), and all temperatures arein degrees Centigrade (Celsius).

The invention is a stabilized thickened hydrogen peroxide containingcomposition. It comprises hydrogen peroxide, water, a polymericthickening agent, and a stabilizer system made up of three components: aphosphorus containing stabilizer or mixture of phosphorus containingstabilizers, a stannate stabilizer, and an aromatic chelating agent ormixture of aromatic chelating agents. If the stabilized thickenedhydrogen peroxide containing composition is to be used as a cleaningcomposition, other ingredients that are conventional components ofcleaning compositions, such as a surfactant or a mixture of surfactants,are present.

Polymeric Thickening Agent

The stabilized thickened hydrogen peroxide containing compositioncomprises a polymeric thickening agent or a mixture of polymericthickening agents, which helps control dispensing of the composition,retards drainage from non-horizontal surfaces to which the compositionis applied, and helps suspend other components of the composition.Although the concentration of the polymeric thickening agent or agentswill depend on the viscosity desired for the final composition, thenature of the polymeric thickening agent or agents present, and thenature and concentration of other materials present in the composition,the stabilized thickened hydrogen peroxide containing compositiontypically comprises about 0.01 to about 10 wt %, preferably 0.05 toabout 5 wt %, more preferably about 0.05 to about 2.5 wt %, and stillmore preferably about 0.25 to about 2.0 wt % of the polymeric thickeningagent, or if more than one polymeric thickening agent is present,agents. The polymeric thickening agents can be dispersed in water andneutralized with base to thicken the hydrogen peroxide containingcomposition and form a gel.

Polymeric thickening agents include, for example, synthetic polymers,cellulose esters, and biopolymers. Synthetic polymers include, forexample, homopolymers and copolymers of olefinically unsaturatedcarboxylic acid and/or anhydride monomers, such as acrylic acid,methacrylic acid, maleic anhydride, itaconic anhydride, etc. A preferredcarboxylic acid is acrylic acid. The copolymers are preferablycopolymers of a carboxylic acid monomer and a hydrophobic monomer.Typically hydrophobic monomers include long chain carbon chain acrylateor methacrylate esters such as decyl acrylate, lauryl acrylate, stearylacrylate, behenyl acrylate, and the corresponding methacrylate esters,and aromatic monomers, such as styrene and substituted styrenes. Thesepolymers typically have molecular weights of about 10,000 to about900,000 or more. The polymers may also be crosslinked. Other usefulpolymeric thickening agents are disclosed in Ambuter, U.S. Pat. No.5,997,764, column 6, line 1, to column 7, line 29, the disclosure ofwhich is incorporated herein by reference.

Cellulose esters include, for example, carboxymethyl cellulose, methylcellulose, ethyl cellulose, hydroxypropyl cellulose, hydroxypropylmethyl cellulose, etc. Biopolymers include, for example, xanthan gum,locust bean gum, guar gum, carob bean gum, konjac, carrageenans,alginates, pectin, etc. Xanthan gum, for example, is a high molecularweight polysaccharide produced by the microorganism Xanthomonascampestris.

The viscosity of the thickened hydrogen peroxide composition will dependon the polymeric thickening agent or agents used in the composition,their concentration, and the viscosity desired for the intended use ofthe composition. Polyacrylate thickening agents typically provide aviscosity of about 10,000 to 100,000 cP. Xanthan gum thickening agenttypically provides a viscosity of about 500 cP to about 1,500 cP. Toothwhitening gels typically have a viscosity of greater than about 10,000cP. Liquid detergents, which must be pourable, typically have aviscosity of about 500 cP to about 2,000 cP.

Stabilizer System

The stabilized thickened hydrogen peroxide containing compositionscomprise a three component stabilizer system. The stabilizer systemcomprises: (a) about 10 ppm to about 1 wt %, preferably about 15 ppm toabout 2500 ppm (0.25 wt %), more preferably about 20 ppm to about 1000ppm (0.1 wt %), even more preferably about 50 ppm to about 500 ppm, of astannate stabilizer; (b) about ppm to about 1 wt %, preferably about 15ppm to about 2500 ppm (0.25 wt %), more preferably about 20 ppm to about1000 ppm (0.1 wt %), even more preferably about 40 ppm to about 500 ppm,of a phosphorus containing stabilizer or, if more than one phosphoruscontaining stabilizer is used, of a mixture of phosphorus containingstabilizers; and (c) about 10 ppm to about 1 wt %, preferably about ppmto about 2500 ppm (0.25 wt %), more preferably about 20 ppm about to1000 ppm (0.1 wt %), even more preferably about 30 ppm to about 600 ppm,of an aromatic chelating agent or, if more than one aromatic chelatingagent is used, of a mixture of aromatic chelating agents. In oneembodiment, the stabilizer system comprises about 30 ppm to about 500ppm, typically 60 ppm to 300 ppm, of each of three components.Typically, the upper limit for the amount of each component and for thesystem as a whole will be determined by economics and by the degree ofstabilization required.

As will be apparent to those skilled in the art, in certain pH rangesone or more of these stabilizer components may be present as itscorresponding anion or anions, or as an equilibrium mixture of thecomponent and its corresponding anion or anions. Anions of thesestabilizer components and mixtures of these stabilizer components andtheir corresponding anion or anions are included in the definition ofeach of these stabilizer components and are within the scope of theclaims.

Phosphorus containing stabilizers include pyrophosphates (such as, forexample, Na₄P₂O₇, Na₃HP₂O₇, Na₂H₂P₂O₇, and K₂H₂P₂O₇) and phosphonic acidchelating agents. Phosphonic acid chelating agents include, for example,compounds of the general structure N(CR¹R²PO₃H₂)₃, in which R¹ and R²are each independently hydrogen or an alkyl group of one to four carbonatoms, such as amino tri(methylene phosphonic acid) (ATMP) (DEQUEST®2000, Solutia, St. Louis, Mo., USA), in which R¹ and R² are eachhydrogen; diethylene triamine penta(methylene phosphonic acid) (DTPA)(DEQUEST® 2066); hexamethylene diamine tetra(methylene phosphonic acid)(DEQUEST® 2054); bis hexamethylene triamine penta methylene phosphonicacid (DEQUEST®) 2090); and compounds of the general structureC(R³)(PO₃H₂)₂OH, in which R³ is hydrogen or an alkyl group of one tofour carbon atoms, such as 1-hydroxyethylidene-1,1-diphosphonic acid(HEDP) (DEQUEST® 2010) (C(CH₃)(PO₃H₂)₂OH). Preferred phosphorus-basedchelating agents include 1-hydroxyethylidene-1,1-diphosphonic acid,amino tri(methylene phosphonic acid), and diethylene triaminepenta(methylene phosphonic acid).

The stannate stabilizer may be formed in situ from hydrolysis of a tincompound, such as tin sulfate, sodium stannate (Na₂SnO₃.3(H₂O)), tindichloride, or tin tetrachloride. Although the stannate stabilizer isbelieved to be colloidal stannic oxide, it is typically referred to ascolloidal sodium stannate or sodium stannate.

The thickened hydrogen peroxide containing composition comprises anaromatic chelating agent or a mixture of aromatic chelating agents.While not being bound by any theory of explanation, it is believed thatthis compound functions as a radical scavenger. The aromatic structureincludes carbocyclic aromatic rings, such as the benzene or naphthalenering, as well as heteroaromatic rings such as pyridine and quinoline.The stabilizer should also contain chelating groups, such as hydroxyl,carboxyl, phosphonate, or sulfonate.

The aromatic chelating agent may be, for example, salicylic acid; asubstituted salicylic acid, such as 3-methylsalicylic acid, 4-methylsalicylic acid, 5-methyl salicylic acid, 6-methyl salicylic acid,3,5-dimethyl salicylic acid, 3-ethyl salicylic acid, 3-iso-propylsalicylic acid, 3-methoxy salicylic acid, 4-methoxy salicylic acid,5-methyoxy salicylic acid, 6-methoxy salicylic acid, 4-ethoxy salicylicacid, 5-ethyoxy salicylic acid, 2-chloro salicylic acid, 3-chlorosalicylic acid, 4-chloro salicylic acid, 5-choloro salicylic acid,3,5-dichloro salicylic acid, 4-fluoro salicylic acid, 5-fluoro salicylicacid, 6-fluoro salicylic acid; or a mixture thereof. The aromaticchelating agent may be, for example, 8-hydroxy-quinoline; a substituted8-hydroxy-quinoline, such as, 5-methyl-8-hydroxy-quinoline,5-methoxy-8-hydroxy-quinoline, 5-chloro-8-hydroxy-quinoline,5,7-dichloro-8-hydroxy-quinoline, 8-hydroxy-quinoline-5-sulfonic acid,or a mixture thereof. The aromatic chelating agent may be, for example,a pyridine-2-carboxylic acid, such as picolinic acid(2-pyridinecarboxylic aid); dipicolinic acid (2,6-pyridinedicarbxylicacid); 6-hydroxy-picolinic acid; a substituted 6-hydroxy-picolinic acid,such as 3-methyl-6-hydroxy-picolinic acid, 3-methoxy-6-hydroxy-picolinicacid, 3-chloro-6-hydroxy-picolinic acid,3,5-dichloro-6-hydroxy-picolinic acid; or a mixture thereof. Preferredaromatic chelating agents include, salicylic acid, 6-hydroxy-picolinicacid, and 8-hydroxy-quinoline.

Other Ingredients

The stabilized thickened hydrogen peroxide containing composition can beused as, for example, a disinfectant lotion or in the oxidative dying ofhair. However, if the stabilized thickened hydrogen peroxide containingcomposition is to be used a cleaning composition, it may comprise othercomponents that are conventional ingredients of cleaning compositions.

The composition may also comprise a surfactant or a mixture ofsurfactants. Numerous surfactants useful in cleaning compositions arewell known. Surfactants are well known to those skilled in the art andare described, for example, in McCutcheon's Detergents and Emulsifiers,Manufacturing Confectioners Publishing Company, Glen Rock, N.J., and inEncyclopedia of Surfactants, Volumes I–III, Compiled by M. and I. Ash,Chemical Publishing Co., NY. Surfactants useful in cleaning compositionsare disclosed in, for example, Wise, U.S. Pat. No. 5,169,552; Gosselink,U.S. Pat. No. 4,702,857, especially column 17, line 27, to column 22,line 19, and Laughlin, U.S. Pat. No. 3,929,678, especially column 5,line 65, to column 36, line 30. The concentration of the surfactant orthe mixture of surfactants is typically about 0.25 wt % to about 25 wt%, more typically about 1.0 wt % to 15 wt %, of the composition.Preferably the surfactant or surfactants do not contain functionalgroups that are susceptible to oxidation by the hydrogen peroxide, suchas carbon carbon double bonds, hydroxyl groups, etc.

Nonionic surfactants are typically condensation products of ahydrophobic organic aliphatic compound, such as a long chain aliphaticalcohol, and hydrophilic ethylene oxide and/or propylene oxide. Thelength of the resulting polyether chain can be adjusted to achieve thedesired balance between the hydrophobic and hydrophilic properties.Nonionic surfactants include, for example, ethoxylated and propoxylatedalcohols, especially C₈₋₂₀ alcohols, with 2 to 100 moles of ethyleneoxide and/or propylene oxide per mole of alcohol, especially ethoxylatesof primary alcohols containing about 8 to 18 carbon atoms in a straightor branched chain configuration with about 5 to 30 moles of ethyleneoxide, for example, the ethoxylates of decyl alcohol, cetyl alcohol,lauryl alcohol, or myristyl alcohol; ethoxylates of secondary aliphaticalcohols containing 8 to 18 carbon atoms in a straight or branched chainconfiguration with 5 to 30 moles of ethylene oxide; condensation ofaliphatic alcohols containing about 8 to abut 20 carbon atoms withethylene oxide and propylene oxide; polyethylene glycol and polyethyleneoxide; ethoxylated hydrogenated castor oil; and ethoxylates of sorbitanesters.

Anionic surfactants include, for example, alkyl ether phosphates, alkylaryl sulphonates, alkyl ether sulphates, alkyl sulphates, arylsulphonates, carboxylated alcohol ethoxylates, olefin sulphonates,succinates, fatty acid soaps, alkyl diphenyl disulfonates, etc., andmixtures thereof. Examples of anionic surfactants are: sodium cetylsulfate, sodium lauryl sulfate (SLS), sodium myristyl sulfate, andsodium stearyl sulfate, sodium dodecylbenzene sulfonate, and sodiumpolyoxyethylene lauryl ether sulfate.

Other conventional ingredients may be included, provided each ingredientis compatible with the other ingredients of the thickened hydrogenperoxide containing composition and the presence of the ingredient doesnot adversely affect the properties of the thickened hydrogen peroxidecontaining composition. Each additional ingredient is used to modify thethickened hydrogen peroxide containing composition in conventional formand is present in an effective amount, that is, in the amount requiredto achieve the desired effect without adversely affecting the propertiesof the composition.

The stabilized thickened hydrogen peroxide containing compositions usedin, for example, cleaning applications, may also comprise a perfumes andfragrances, typically at about 0.03 to about 0.5 wt % of thecomposition. Fluorescent whitening agents may also be present, typicallyat about 0.1 to 1.0 wt %. An anti-redeposition agent, such as, polyvinylpyrrolidone, hydroxyethyl cellulose, sodium carboxymethyl cellulose, andhydroxypropyl ethyl cellulose may be present. A filler salt, such assodium sulfate or sodium chloride, may be present. Other conventionalingredients include: dyes and other colorants; fabric softeningcompositions; static control agents; optical opacifiers, such aspolystyrene particles; and suds regulants, such as dimethylpolysiloxane.

The stabilizer system may be used over a wide pH range. However, the pHof the stabilized thickened hydrogen peroxide containing composition maybe less than about 9, typically less than about 8, more typically about3 to about 7, even more typically about 5 to about 7. Although a buffer,such as a phosphate buffer, may be included to maintain pH at thedesired value, this may not be necessary in all cases.

Hydrogen Peroxide

The stabilized thickened hydrogen peroxide containing compositiontypically comprises about 0.5 wt % to about 15 wt %, typically about 1wt % to about 10 wt %, more typically about 2 wt % to about 8 wt %, evenmore typically about 3 wt % to about 5 wt %, of hydrogen peroxide.Hydrogen peroxide (H₂O₂) is commercially available, and its preparationhas been described in numerous patents and publication. Theanthraquinone process (also called the autoxidation process or theRiedl-Pfleiderer process) is described, for example, in Riedl, U.S. Pat.No. 2,158,525, and in the Kirk-Othmer Encyclopedia of ChemicalTechnology, 3rd. ed., Volume 13, Wiley, New York, 1981, pp. 15–22.

It may be necessary to add base, such as aqueous sodium hydroxide oraqueous potassium hydroxide, to the composition until the desired pH isattained. Aqueous sodium hydroxide is preferred. The base should be freefrom metal ions that would catalyze decomposition of hydrogen peroxide,such as ferrous ions, ferric ions, cupric ions, cuprous ions, manganousions, and similar transition metal ions. The base should also be freefrom both organic and inorganic materials that would react with thehydrogen peroxide.

After all the other ingredients have been accounted for, water comprisesthe balance of the thickened hydrogen peroxide containing composition.Because hydrogen peroxide is typically commercially available as a 30 wt% to 70 wt % aqueous solution, it is typically necessary to dilute thehydrogen peroxide with water to obtain the desired hydrogen peroxideconcentration. The water should be free from metal ions that wouldcatalyze decomposition of hydrogen peroxide, such as ferrous ions,ferric ions, cupric ions, cuprous ions, manganous ions, and similartransition metal ions. The water should also be free from organicmaterial that would be oxidized by hydrogen peroxide. The water shouldalso be free of inorganic materials that would react with hydrogenperoxide, such as chlorine (Cl₂), hypochorous acid (HOCl), and sodiumhypochlorite (NaOCl). Distilled or deionized water is preferred.

INDUSTRIAL APPLICABILITY

The stabilized thickened hydrogen peroxide containing compositions maybe used in a variety of disinfectant, cleaning, personal care,pharmaceutical, textile and industrial applications. They disinfect thesurfaces into which they are brought into contact and so can be used asdisinfectant solutions or disinfectant lotions. When a surfactant ispresent, they both clean and disinfect the surfaces into which they arebrought into contact. They can be applied by any method that insuresgood contact between the object to be cleaned and/or disinfected and thecomposition, such as spraying or wiping, and then removed by, forexample, rinsing with water and/or wiping. The stabilized thickenedhydrogen peroxide containing compositions may also be used, for example,as liquid detergents and in oral care applications, such as in toothbleaching compositions.

They can also be used in oxidative dying, which is extensively used forthe dying of hair. In the oxidative dying process, hydrogen peroxide isused in combination with one or more oxidative hair coloring agents,generally small molecules capable of diffusing into hair and comprisingone or more primary intermediates and one or more couplers. The hydrogenperoxide activates the small molecules of primary intermediates so thatthey react with couplers to form larger sized compounds in the hairshaft to color the hair in a variety of shades and colors. Typicalprimary intermediates include p-phenylenediamine, p-toluenediamine,p-aminophenol, and 4-amino-3-methylphenol. Typical couplers includeresorcinol, 2-methylresorcinol, 3-aminophenol, and5-amino-2-methylphenol. The color depends on the primary intermediate(s)and coupler(s) used. Typically, the hydrogen peroxide is a 3 wt % to 12wt %, preferably a 6 wt %, aqueous solution, which can be a viscousliquid or gel. In general, the hair dyeing composition comprising theprimary intermediate(s) and coupler(s) is prepared and then, at the timeof use, mixed with the stabilized thickened hydrogen peroxide containingcomposition until an essentially homogenous composition is obtained.Shortly after its preparation, the resulting composition is applied tothe hair to be dyed and permitted to remain in contact with the hair forabout 2 to about 60 min, typically about 15 to 45 min, especially about30 min, at about 15 to 50° C. The hair is rinsed with water, and dried.If necessary, it is washed with a shampoo and rinsed, e.g., with wateror a weakly acidic solution, such as a citric acid or tartaric acidsolution. Subsequently the hair is dried.

The advantageous properties of this invention can be observed byreference to the following examples, which illustrate but do not limitthe invention.

EXAMPLES Glossary

-   -   ACULYN® 28 Acrylates/Beheneth-25 Methacrylate Copolymer (Rohm        and Haas, Philadelphia, Pa., USA)    -   CARBOPOL® 2020 Polyacrylate polymeric thickening agent (Noveon,        Cleveland, Ohio, USA)    -   CARBOPOL® EZ-2 Polyacrylate polymeric thickening agent (Noveon,        Cleveland, Ohio, USA)    -   CARBOPOL® EZ-3 Polyacrylate polymeric thickening agent (Noveon,        Cleveland, Ohio, USA)    -   DTPA Diethylene triamine penta(methylene phosphonic acid)        (DEQUEST® 2066) (Solutia, St. Louis, Mo., USA)    -   HEDP 1-Hydroxyethylidene-1,1-diphosphonic acid (DEQUEST® 2010)        (Solutia, St. Louis, Mo., USA)    -   RHODOPOL® T Xanthum gum polymeric thickening agent (Rhodia,        Cranbury, N.J., USA)    -   Sodium Stannate Sodium stannate, Na₂SnO₃.3H₂O    -   Pyrophosphate Na₂H₂P₂O₇

General Procedures Preparation Stabilized 50% Hydrogen PeroxideSolutions

Stabilizers were mixed with deionized water to make a standardstabilizer system solution. The 50% stabilized hydrogen peroxidesolution was prepared by adding the stabilizer system to 70% hydrogenperoxide, and diluting the resulting stabilized hydrogen peroxide to 50%hydrogen peroxide with deionized water.

Preparation of Thickened Hydrogen Peroxide Containing Compositions

Except where indicated, the samples contain 5–6% hydrogen peroxide and0.4–3% polymeric thickening agent. The polymeric thickening agent (0.7g) was added to 60 g of deionized water and mixed well. The stabilizerswere added to the hydrogen peroxide solutions before the polymericthickening agents. Sodium hydroxide solution (8%) was added until themixture thickened. 50% Hydrogen peroxide (7 ml) and water were added tomake 70 g of the thickened hydrogen peroxide containing composition,which was a hydrogen peroxide containing gel. The pH was adjusted to 5to 7 with 8% aqueous sodium hydroxide. The stabilizer concentrationgiven for each sample is the concentration of the active ingredient inthe final sample.

Stability Evaluation

Unless otherwise indicated, the following procedure was followed forstability evaluation. The samples were put in a 40° C. to 50° C. oven.The viscosity of the composition and, in some cases, the concentrationof hydrogen peroxide in the composition, was measured during the storageperiod. Viscosity, in cP, was measured with Brookfield RVTD DigitalViscometer and Brookfield KYNAR® resin coated spindle #6T. Hydrogenperoxide concentration was measured by titration with potassiumpermanganate.

Example 1

This example shows the change in viscosity and hydrogen peroxideconcentration for samples that contain a polyacrylate polymericthickening agent and various stabilizers. The following samples wereprepared and evaluated as described in the General Procedures. Theresults are shown in Table 1.

Each of the samples contained 5 wt % hydrogen peroxide and 1 wt %CARBOPOL® EZ-2 polymeric thickening agent. The pH was 6. The storagetemperature was 45° C.

Sample 1-A contains <1 ppm of Na₂H₂P₂O₇.

Sample 1-B contains 150 ppm of salicylic acid and <1 ppm of Na₂H₂P₂O₇.

Sample 1-C contains 150 ppm of HEDP and <1 ppm of Na₂H₂P₂O₇.

Sample 1-D contains 300 ppm of sodium stannate and <1 ppm of Na₂H₂P₂O₇.

Sample 1-E contains 300 ppm of sodium stannate, 150 ppm of HEDP, 150 ppmof salicylic acid and <1 ppm of Na₂H₂P₂O₇.

TABLE 1 Time (weeks) Examples 0 1 2 3 1-A Viscosity (cP) 37,500 50 ND^(a) ND H₂O₂ (wt %) 4.84 0.76 ND ND 1-B Viscosity (cP) 50,000 50 NDND H₂O₂ (wt %) 4.97 0.98 ND ND 1-C Viscosity (cP) 50,000 14,000 50 NDH₂O₂ (wt %) 4.70 4.79 1.15 ND 1-D Viscosity (cP) 50,000 43,500 37,50019,000 H₂O₂ (wt %) 4.81 4.78 4.77 4.75 1-E Viscosity (cP) 50,000 42,00039,000 36,500 H₂O₂ (wt %) 4.88 4.76 4.69 4.55 ^(a)ND means notdetermined.

Sample 1-A contains almost no stabilizer, and Samples 1-B to 1-D containonly one of the stabilizers. Both the viscosity and the hydrogenperoxide concentration of these samples rapidly decreased on storagetemperature at 45° C. Although the hydrogen peroxide concentration ofSample 1-D, the sodium stannate containing sample, did not decrease asrapidly as in the other samples, the viscosity of this sample decreasedduring the test period.

Sample 1-E contains a stabilizer system of the invention. Both viscosityand hydrogen peroxide decreased less during the test period.

Example 2

This example shows the change in viscosity for samples that contain apolyacrylate polymeric thickening agent and a stabilizer system of theinvention. The following samples were prepared and evaluated asdescribed in the General Procedures. The results are shown in Table 2.

Each of the samples contained 5 wt % hydrogen peroxide and 3 wt %ACULYN®28 polymeric thickening agent. The pH is adjusted to 6. Thestorage temperature is 45° C.

Sample 2-A contains less than 1 ppm Na₂H₂P₂O₇.

Sample 2-B contains 300 ppm sodium stannate, 150 ppm HEDP, 150 ppmsalicylic acid, and less than 1 ppm Na₂H₂P₂O₇.

TABLE 2 Time (weeks) Examples 0 1 2 3 4 5 6 2-A Viscosity (cP) 50000 50ND ND ND ND ND H₂O₂ (wt %) 4.37 0.43 ND ND ND ND ND 2-B Viscosity (cP)50000 50000 50000 50000 50000 42000 41000 H₂O₂ (wt %) 4.06 3.93 3.9 3.913.88 3.94 3.81

Sample 2-A contains almost no stabilizer. Both the viscosity and thehydrogen peroxide concentration of this sample rapidly decreased onstorage temperature at 45° C.

Sample 2-B contains a stabilizer system of the invention. Both viscosityand hydrogen peroxide decreased only slightly during the six-week testperiod.

Example 3

This example shows the change in viscosity for samples that contain apolyacrylate polymeric thickening agent and a stabilizer system of theinvention. The following samples were prepared and evaluated asdescribed in the General Procedures. The results, showing viscosity incP, are shown in Table 3.

Each of the samples contained 1 wt % 1% CARBOPOL® 2020 polymericthickening agent. The pH is adjusted to 7. The storage temperature is50° C.

Sample 3-A contained 0 wt % hydrogen peroxide.

Sample 3-B contained 5 wt % hydrogen peroxide and <1 ppm Na₂H₂P₂O₇.

Sample 3-C contained 5 wt % hydrogen peroxide, 40 ppm Na₂SnO₃ 3H₂O, 200ppm HEDP, 500 ppm 6-hydroxyl picolinic acid, and <1 ppm Na₂H₂P₂O₇.

TABLE 3 Time (weeks) Examples^(a) 0 1 2 3 4 3-A 128,000 46,000 15,400  600   800 3-B 134,200 800 ND ND ND 3-C 112,400 60,600 41,000 33,60028,600 ^(a)Viscosity, in cP

Sample 3-B contained less than 1 ppm of stabilizers. The viscosityreduced more than 90% within 1 week. The viscosity of sample 3-C, whichcontained a stabilizer system of the invention, decreased less than thatof Sample 3-A, which does not contain hydrogen peroxide.

Example 4

This example shows the change in viscosity for samples that contain apolyacrylate polymeric thickening agent and a stabilizer system of theinvention. The following samples were prepared and evaluated asdescribed in the General Procedures. The results, showing viscosity incP, are shown in Table 4.

Each of the samples contained 1 wt % CARBOPOL® EZ 3 polymeric thickeningagent. The pH was adjusted to 5. The storage temperature was 50° C.

Sample 4-A contained 0% hydrogen peroxide.

Sample 4-B contained 5% hydrogen peroxide and <1 ppm Na₂H₂P₂O₇.

Sample 4-C contained 5% hydrogen peroxide, 80 ppm Na₂SnO₃ 3H₂O, 40 ppmNa₂H₂P₂O₇, 50 ppm of 8-hydroxy quinoline, and <1 ppm Na₂H₂P₂O₇.

TABLE 4 Time (week) Examples^(a) 0 1 2 3 4 4-A 180,800 ND 128,600 89,60074,000 4-B 0 0 0 0 0 4-C 194,600 ND 135,200 98,400 43,800 ^(a)Viscosity,in cP

Sample 4-B, with no stabilizer, could not maintain viscosity while beingprepared. During the test period, Sample 4-C, which contains astabilizer system of the invention, was comparable in stability toSample 4-A, which does not contain hydrogen peroxide.

Example 5

This example shows the change in viscosity for samples that contain astabilizer system of the invention and xanthan gum as the polymericthickening agent. Except were indicated, the following samples wereprepared and evaluated as described in the General Procedures. Thethickening agent was 0.4% RHODOPOL® T xanthan gum. The pH was adjustedto 5 with 85% phosphoric acid (2 ppm). The storage temperature was 40°C. Viscosities, in cP, for these samples, were measured with theBrookfield DVII Viscometer and Brookfield spindle #2. The results,showing viscosity in cP, are shown in Table 5.

Sample 5-A contained 0% hydrogen peroxide.

Sample 5-B contained 6% hydrogen peroxide, 2 ppm of Na₂H₂P₂O₇ and 625ppm DEQUEST® 2066.

Sample 5-C contained 6% hydrogen peroxide with 2 ppm Na₂H₂P₂O₇, 625 ppmDEQUEST® 2066, and 500 ppm sodium salicylate.

Sample 5-D contained 6% hydrogen peroxide with 2 ppm Na₂H₂P₂O₇, 625 ppmDEQUEST® 2066, 500 ppm sodium salicylate, and 25 ppm sodium stannate.

TABLE 5 Time (days) Examples^(a) 0 6 7 14 21 24 28 5-A 1105 ND  937 895847 ND 720 5-B 1175 1130 ND 972 802 672 ND 5-C 1252 ND 1207 1092 942 ND637 5-D 1260 ND 1233 1155 1070 ND 930 ^(a)Viscosity, in cP

With a stabilizer system of the invention, sample 5-D is much morestable than Sample 5-B, which only contains phosphorus-based stabilizersand Sample 5-C, which contains phosphonate and salicylate asstabilizers. It appears to be even more stable than the sample withouthydrogen peroxide (5-A).

Having described the invention, we now claim the following and theirequivalents.

1. A composition comprising: a) about 0.5 wt % to about 15 wt % ofhydrogen peroxide; b) water; c) about 0.01 wt % to 10 wt % of apolymeric thickening agent or a mixture of polymeric thickening agents;and d) a stabilizer system comprising; i) about 10 ppm to about 1% of astannate stabilizer; ii) about 10 ppm to about 1% of a phosphoruscontaining stabilizer or a mixture of phosphorus containing stabilizers;and iii) about 10 ppm to about 1% of an aromatic chelating agentselected from the group consisting of 6-hydroxy-picolinic acid,substituted 6-hydroxy-picolinic acid, 8-hydroxy-quinoline, substituted8-hydroxy-quinolines pyridine-2-carboxylic acid and mixtures thereof; inwhich the composition has a viscosity of greater than about 500 cP. 2.The composition of claim 1 in which the composition comprises about 15ppm to about 2500 ppm of the stannate stabilizer; about 15 ppm to about2500 ppm of the phosphorus containing stabilizer or the mixture ofphosphorus containing stabilizers; and about 15 ppm to about 2500 ppm ofthe aromatic chelating agent or the mixture of aromatic chelatingagents.
 3. The composition of claim 2 in which: the phosphoruscontaining stabilizer or stabilizers are selected from the groupconsisting of pyrophosphate, compounds of the structure N(CR¹R²PO₃H₂)₃,in which R¹ and R² are each independently hydrogen or an alkyl group ofone to four carbon atoms, diethylene triamine penta(methylene phosphonicacid), hexamethylene diamine tetra(methylene phosphonic acid), bishexamethylene triamine penta methylene phosphonic acid, and compounds ofthe general structure C(R³)(PO₃H₂)₂OH, in which R³ hydrogen or an alkylgroup of one to four carbon atoms.
 4. The composition of claim 3 inwhich the polymeric thickening agent or polymeric thickening agents areselected from the group consisting of homopolymers and copolymers ofacrylic acid, and the composition comprises about 0.05 wt % to about 5wt % of the polymeric thickening agent.
 5. The composition of claim 4 inwhich the composition has a pH of about 3 to about
 7. 6. The compositionof claim 5 in which the composition comprises about 20 ppm to about 1000ppm of the stannate stabilizer; about 20 ppm to about 1000 ppm of thephosphorus containing stabilizer or the mixture of phosphorus containingstabilizers; and about 20 ppm to about 1000 ppm of the aromaticchelating agent or the mixture of aromatic chelating agents.
 7. Thecomposition of claim 6 in which the composition comprises about 50 ppmto about 500 ppm of the stannate stabilizer; about 40 ppm to about 500ppm of the phosphorus containing stabilizer or the mixture of phosphoruscontaining stabilizers; and about 30 ppm to about 600 ppm of thearomatic chelating agent or the mixture of aromatic chelating agents. 8.The composition of claim 7 in which the phosphorus containing stabilizeror stabilizers are selected from the group consisting of pyrophosphate,amino tri(methylene phosphonic acid), diethylene triaminepenta(methylene phosphonic acid), hexamethylene diamine tetra(methylenephosphonic acid), bis hexamethylene triamine yenta methylene phosphonieacid, and 1-hydroxyethylidene-1,1-diphosphonic acid; and the aromaticchelating agent or agents are selected from the group consisting of6-hydroxy-picolinic acid and 8-hydroxy-quinoline.
 9. The composition ofclaim 1 in which the composition additionally comprises about 0.25 wt %to about 25 wt % of a surfactant or a mixture of surfactants.
 10. Thecomposition of claim 9 in which the composition comprises about 15 ppmto about 2500 ppm of the stannate stabilizer; about 15 ppm to about 2500ppm of the phosphorus containing stabilizer or the mixture of phosphoruscontaining stabilizers; and about 15 ppm to about 2500 ppm of thearomatic chelating agent or the mixture of aromatic chelating agents.11. The composition of claim 10 in which the composition has a pH ofabout 3 to about
 7. 12. The composition of claim 11 in which thecomposition has a viscosity of about 10,000 cP to about 100,000 cP. 13.The composition of claim 12 in which the thickening agent is apolyacrylate thickening agent.
 14. The composition of claim 11 in whichthe composition has a viscosity of about 500 cP to about 2,000 cP. 15.The composition of claim 14 in which the thickening agent is xanthangum.
 16. The composition of claim 11 in which the phosphorus containingstabilizer or stabilizers are selected from the group consisting ofpyrophosphate, compounds of the structure N(CR¹R²PO₃H₂)₃, in which R¹and R² are each independently hydrogen or an alkyl group of one to fourcarbon atoms, diethylene triamine penta(methylene phosphonic acid),hexamethylene diamine tetra(methylene phosphonic acid), bishexamethylene triamine penta methylene phosphonic acid, and compounds ofthe general structure C(R³)(PO₃H₂)₂OH, in which R³ is hydrogen or anailcyl group of one to four carbon atoms.
 17. The composition of claim16 in which the composition comprises about 20 ppm to about 1000 ppm ofthe stannate stabilizer; about 20 ppm to about 1000 ppm of thephosphorus containing stabilizer or the mixture of phosphorus containingstabilizers; and about 20 ppm to about 1000 ppm of the aromaticchelating agent or the mixture of aromatic chelating agents.
 18. Thecomposition of claim 17 in which the composition comprises about 50 ppmto about 500 ppm of the stannate stabilizer; about 40 ppm to about 500ppm of the phosphorus containing stabilizer or the mixture of phosphoruscontaining stabilizers; and about 30 ppm to about 600 ppm of thearomatic chelating agent or the mixture of aromatic chelating agents.19. The composition of claim 18 in which the phosphorus containingstabilizer or stabilizers are selected from the group consisting ofpyrophosphate, amino tri(methylene phosphonic acid), diethylene triaminepenta(methylene phosphonic acid), hexaxmethylene diamine tetra(methylenephosphonic acid), bis hexamethylene triamine penta methylene phosphonicacid, and 1-hydroxyethylidene-1,1-diphosphonic acid; and the aromaticchelating agent or agents are selected from the group consisting of6-hydroxy-picolinic acid and 8-hydroxy-quinoline.
 20. The composition ofclaim 19 in which the composition comprises about 0.05 wt % to about 2.5wt % of the polymeric thickening agent and about 2 wt % to 8 wt % ofhydrogen peroxide.
 21. The composition of claim 20 in which thecomposition has a viscosity of about 10,000 cP to about 100,000 cP. 22.The composition of claim 21 in which the thickening agent is apolyacrylate thickening agent.
 23. The composition of claim 20 in whichthe composition has a viscosity of about 500 cP to about 2,000 cP. 24.The composition of claim 23 in which the thickening agent is xanthangum.